Piston for explosive-engines.



wi/ memo I. D. GILLIGAN.

PISTON FOR EXPLOSIVE ENGlN ES.

APPLICATION man MAY 28. 1914.

Patented July 18, 1916.

2 SHEETS-SHEET 1.

J IT D STATES PATENT 1 OFFICE.

Jorm D. GILLIGAN, OFRHINELANDER, Wiscons n.

PISTON FOR EXPLOSIVE-ENGINES.

To all whom it may concern:

Be it known that I, JOHN D. GILLIGAN, citizen of the United States,residing at Rhinelander, in the county of Oneida and 5 State ofWisconsin, have invented certain new and useful Improvements in Pistonsfor Explosive-Engines, of which the following is a specification.

My invention relates to. improvements in pistons for explosive enginesof any class where the power is applied to a reciprocating piston by theexplosion of a charge of gas, vapor, or other material that may be used,the nature of which is to impart its energy in impulses of great initialforce, but of short duration.

The object of the invention is to provide an auxiliary piston that willabsorb a portion of the energy liberated by a charge of fuel having thecharacteristics described, and which will contribute the power or forceso held and reserved by the said auxiliary piston to the piston properat a time later in the stroke, when the direct effect of the explod ingcharge has been diminished.

The force of an exploding charge within the cylinder of an ordinaryengine of the class described is so violent and comes with such suddenvigor that the efiect upon the mechanism of the engine is similar to theresult that would follow from the concussion produced by sledge hammerblows ofequal force.

My improved piston may be made a part of the ordinary reciprocatingpiston, or it may be an independent auxiliary piston a(l.-'-

justable so as to enlarge the contents of the cylinder at the time ofthe severest effect of the explosion, and, then by returning to itsformer'condition in virtue of'the compressed resilient elementassociated therewith, reduce the contents of the cylinder to'its normalcapacity, and thereby impart to the moving pistonthe energy that wouldbestored in the said element, which is compressed by the said auxiliarypiston at the instant of the explosion. 3,

' Theabove and additional objects are accomplished by such means as areillustrated 5min their preferred embodiment in the accompanyingdrawings, described in the following specification and then moreparticus Specification of Letters Patent.

Application i il edllay 28, 1914. Serial No. 841,639.

2 Patented July 18,1916.

larly pointed out in the claims which areap pended hereto and form apartof this application. I

In describing my invention in detail ref,- erence will be had to theaccompanying drawings wherein like characters denote like orcorresponding parts throughout the severalviews, and in which Figure 1is an elevation of my improved piston, the engine cylinder in connectionwith which it is used, being shown in section; Fig. 2 is a longitudinalsectional view of the piston; Fig. 3 is an inverted plan View of thepiston, the piston rod or pitman being shown in section; and Fig. 4 is asection on the line 4-4 of Fig. 2.

Referring now to the drawings by numerals, 1 designates the cylinder ofan ordinary explosive engine, 2 the water jacket, 3 the crank case, andithe crank shaft, the -con-.

struction of which may be varied or modified to an unlimited degreewithout in any way departing from the spirit of the present ,invention.

A reciprocating piston, designated as an' entirety by the numeral 5 isoperable within the cylinder 1, a pitman or piston rod 6 C011".-

necting the said piston to the crank shaft 1 indicated at 9to the pitmanor piston rod 6.

Piston proper 7 is engageable with the interior wall of the cylinder 1,packing rings 10 being associated therewith for an obvious purpose. Thepiston proper 7, as illustrated,

to advantage in Fig.2, is hollow, one end being closed as indicated at11, said closed end forming an abutment for'one end of a spiral orhelical spring 12 arranged withinthe said pistonproper, its opposite endabutting an annular flange 13 formed integrally with the auxiliarypiston 8, the latter operating within the piston proper 7, the spring 12serving as a means whereby the said piston proper is normally held withits closed end 11 out of engagement with the top edge of the saidauxiliary piston 8, the latter, as shown in the drawings, being hollowor cylindrical in form. As a means whereby movement of auxiliary piston8 is limited, I provide an exteriorly threaded band or ring 14, the

threads of I which are engageable with threads formed" upon 'theinterior wall of,

piston proper 7 this arrangement providing for an adjustment of the saidauxiliary piston to vary the length of the stroke of the piston properrelatively thereto when acted upon by the explosion of a charge of fuelwithin the cylinder. Annular flange 13 is engageable with the ring orband 14, such engagement limiting movement of piston proper 7,-holdingthe latter in operative position, and against tension of spring 12.Grooves 15, preferably four in number, and disposed at diametricallyopposite points, are formed within piston proper 7, the grooves beinopen to the interior thereof, as is clearly s own in.Fig. 4. Extensions16 are formed integrally with the flange 13, upon the periphery thereof,the extensions fitting the respective grooves to serve as guide meansfor the piston proper 7 and preventing circumferential movement of onepiston section independently of the other. The grooves and extensionsare preferably dovetailed.

' To provide for the use of a spring offering a maximum of resistance,the auxlliary piston 8 is of a diameter somewhat less than the diameterof the bore of piston proper 7, the space between the exterior wall ofthe auxiliary piston and the interior wall of the piston proper toprovide for the arrange ment of the spring 12 therein, therebypermitting one end of the spring to abut, as above set forth, theannular flange 13 which is formed at a point adjacent the bottom edge ofthe piston section 8, that portion ofthe piston above the .flangeserving as a means whereby the spring is held in place.

From the foregoing, taken in connection with the accompanying drawingsit is apparent that piston proper 7 will be actuated against tension ofspring 12 to receive the shock occasioned by the sudden explosion of afuel charge; that the said spring 12 will return the said piston proper7 to its normal position immediately subsequent to the explosion, theactuating force of the exploded charge being then evenly distributed toin this manner provide for reciprocation of the piston; and that thefierce and violent compression is not imparted to the working parts ofthe engine, a portion thereof being absorbed by the expansible piston,thus providing for a steady even motion or ation of the engine.

In reduction to practice, I have found that the form of my invention,illustrated in the drawings and referred to in the above description, asthe preferred embodiment, is the most eflicient and practical; yetrealizing that the conditions concurrent with the adoption of my devicewill necessarily vary,

oper- I desire to'emphasize the fact that various minor changes indetails of construction, proportion and arrangement of parts may beresorted to, when required, without sacrificing any of the advantages ofmy invention, asdefined in the appended claims.

Having thus fully described my invencure by Letters Patent, is

1. A piston for explosive engines including relatively movable pistonsections, cushioning means interposed between said sections, meansadjustable to vary the tension of said cushioning means, and meansincluding a dove-tailed enlargement formed tion, what I claim as newandv desire to seuponone of said sections to fit a completial movementof one section independently of the other, the said extensions andgrooves serving as guide means for the piston sections when movedrelatively to each other, and spring means interposed between the flangeof one section and one of the defining walls of the other section toform a cushion support, as and for the purpose set forth.

3. A piston for explosive engines including a piston proper closed atone end, an auxiliary piston extending into said piston proper, anannular flange formed integrally with the said auxiliary piston, aspring interposed between the closed end ofsaid piston proper and saidflange, said spring forming a cushion support for the piston proper,dove-tailed extensions'formed upon the periphery of said flange, thesaid extensions fitting dove-tailed grooves formed in the piston properto serve as guide means for the piston sections when moved relatively toeach other, a band adjustable relatively to the piston proper, said bandforming an abutment for the flange ..to limit movement of one of thepiston' sections, movement of said band permitting variation of thespring tension, as and for the purpose set forth. I

4. A piston for explosive engines including a piston proper closed atone end, an auxiliary piston extending into said piston proper, thediameter of the auxiliary piston being less than the diameter of thebore of the piston proper to provide a space therebetween, an annularflange formed integrally with the auxiliary piston, a single springinterposed between the closed end of said piston proper and said flange,said spring embracing the auxiliary piston and fitting the spaceaforesaid, extensions formed band permitting variation of the springten- 0 upon the periphery of the said flange, the sion, as and forthe'purpose set forth.

said extensions fitting grooves therefor In testimony whereof I aflix mysignature zvithin tlhe piston proper to prevent circumin presence of twoWitnesses.

erentia movement 0 one piston section independently of the other, and anexteriorly JOHN GILLIGAN' threaded band adjustable relatively to theWitnesses: piston proper, said loand forming an abut- CHAS. CALKINS,ment'for the said flange, adjustment of the 1 E. H. REED.

